#1 The article/author failed to mention that the rocket was DESTRUCTED. It didn't just spontaneously explode as one would conclude from the article's wording. The difference is important.
#2 The article also failed to mention that the launch originally was planned to have the deluge system and flame deflector in place, but a decision was made to proceed with the launch before they could be put in place. In other words, it was a calculated risk that was also used to evaluate the results of using the motor assembly on a simpler reinforced concrete launch facility. It also revealed the need for additional consideration of landing such a rocket on other planets if no landing facility is constructed ahead of time.